Citation
Wang, Yui Loong (1963) I. Thermal decomposition of Nbutane. II. Flow in entrance section of parallel plates. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/FGRQ9X11. https://resolver.caltech.edu/CaltechTHESIS:11062012155050999
Abstract
Part One
The thermal decomposition of nbutane was investigated in a flow reactor at a pressure of 1 atm, in a temperature range of 460° to 560°C, and at low conversion levels, i.e. 0.06  0.68% for the 460° runs, 0.5  2.3% for the 510° runs, and 3.5 to 8.2% for the 560°C runs. Temperature, velocity, and concentration profiles at the exit end of the reactor were measured to study the effects of energy, momentum, and mass transports on chemical reaction. It was found after analysis of data that the reactor could be treated as an isothermal reactor with plug flow under the prevailing operating conditions.
Two rate expressions were determined for the reaction; one corresponding to a firstorder and the other to a secondorder rate. They are
Firstorder rate = 3.34 x 10^(12) e 54,600/RT (C_4H_(10) lb/ft^3 sec
Secondorder rate = 2.55 x 10^(14) e 56,800/RT (C_4H_(10)^2 lb/ft^3 sec
These two expressions equally well represent the experimental data.
On the basis of the products formed and the rates observed, a Ricetype, freeradical mechanism was proposed for the thermal decomposition of nbutane. The mechanism, which is presented in the section on correlation of data, quantitatively describes the reaction. One major feature of the mechanism is the consideration of secondary reactions at very low conversions.
Part Two
Flow of an incompressible fluid at the entrance section of parallel plates under isothermal, laminar conditions was investigated by solving the twodimensional NavierStokes equations numerically. The NavierStokes equations were transformed into finitedifference equations in terms of stream functions ψ and vorticities ω with a technique developed by de G. Allen. The finitedifference equations were then solved by an iterative procedure on digital computers. From the solution, point velocities and pressure gradients were computed.
Two cases were studied, both with a Reynolds number of 300. Case I had a flat velocity distribution at the entrance to the plates. Case II assumed that potentialflow conditions existed only far upstream from the entrance. For both cases, large velocity and pressure gradients were found near the leading edges of the plates, although they were comparatively smaller in Case II. Also the velocity profiles for small distances from the entrance were found to be slightly concave in the central portion between the plates.
Schlichting and others have solved the boundary layer equation for Case I. Their solutions agree well with the present work at large distances from the entrance but deviate considerably near the leading edges as the boundarylayer equation does not describe the behavior of fluid flow near singular points.
Item Type:  Thesis (Dissertation (Ph.D.)) 

Subject Keywords:  Chemical Engineering 
Degree Grantor:  California Institute of Technology 
Division:  Chemistry and Chemical Engineering 
Major Option:  Chemical Engineering 
Thesis Availability:  Public (worldwide access) 
Research Advisor(s): 

Thesis Committee: 

Defense Date:  1 January 1963 
Record Number:  CaltechTHESIS:11062012155050999 
Persistent URL:  https://resolver.caltech.edu/CaltechTHESIS:11062012155050999 
DOI:  10.7907/FGRQ9X11 
Default Usage Policy:  No commercial reproduction, distribution, display or performance rights in this work are provided. 
ID Code:  7259 
Collection:  CaltechTHESIS 
Deposited By:  Ben Perez 
Deposited On:  09 Nov 2012 19:48 
Last Modified:  21 Dec 2019 04:32 
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